Is that functionality likely to be omitted from Perl 6? Possibly, unless that means forcing people to do silly things like this:

$pattern = qr/[:|]/;
@array = split $pattern;

# instead of

$pattern = '[:|]';
@array = split $pattern;
[download]

Is it officially deprecated? No.

Is it valid Perl? Yes.

Should someone vote down this whole friggin' thread? Yes, please.